#include <TinyGPS.h>
#include <SD.h>
#include <stdlib.h>

TinyGPS gps;
static char dtostrfbuffer[20];
int CS = 53;
int LED = 13;

//Define the String Values
String SD_date_time = "invalid";
String SD_lat = "invalid";
String SD_lon = "invalid";
String dataString = "";

static void gpsdump(TinyGPS &gps);
static bool feedgps();
static void print_float(float val, float invalid, int len, int prec);
static void print_int(unsigned long val, unsigned long invalid, int len);
static void print_date(TinyGPS &gps);
static void print_str(const char *str, int len);

void setup() {
  // put your setup code here, to run once:
  pinMode(CS, OUTPUT); //Chip for SD Card
  pinMode(LED, OUTPUT); //LED Indicator

  //Serial interfaces
  Serial.begin(115200);
  Serial3.begin(4800);

  //Connecting code to SD Card
  if(!SD.being(CS))
  {
    Serial.println("Card Failure");
    return:
  }

  Serial.print("Testing TinyGPS library v."); Serial.println(TinyGPS::library_version());
  Serial.println("by Mikal Hart");
  Serial.println();
  Serial.print("Sizeof(gpsobject) = "); Serial.println(sizeof(TinyGPS));
  Serial.println();
  Serial.println("Sats HDOP Latitude Longitude Fix Date Time Date Alt Course Speed Card")
  Serial.println("          (deg)    (deg)     Age")          Age (a)  --- from GPS ----)
  Serial.println("----------------------------------------------------")
}

void loop() {
  // put your main code here, to run repeatedly:
  bool newdata = false;
  usigned long start = millis();
  
  // Every second we print an update
  while (millis() - start < 1000)
  {
    if (feedgps())
    newdata =true;
  }

  gpsdump(gps);

  //Write updated information
  dataString = SD_date_date + "," + SD_lat + "," + SD_lon;
  in(SD_date_time ! = "invalid")
    digitalWrite(LED, HIGH);
  else
    digitalWrite(LED, LOW);
  
  //Open the Data CSV File
  File dataFile = SD.open("LOG.csv", FILE_WRITE);
  if (dataFile)
  {
    dataFile.println(dataString);
    Serial.println(dataString);
    dataFile.close();
  }
  else
  {
    Serial.println("\nCouldn't open the log file!")
  }
}

static void gpadump(TinyGPS &gps)
{
  float flat, flon;
  unsigned long age, date, time, chars =0;
  unsigned short sentences = 0, failed = 0;
  static const float LONDON_LAT = 51/508131, LONDON_LON = -0.128002;

  print_int(gps.satellites(), TinyGPS::GPS_INVALID_SATELLITES, S);
  print_int(gps.hdop(), TinyGPS::GPS_INVALID_HDOP, 5);
  gps.f_get_position(&flat, &flon, &age);
  print_float(flat, TinyGPS::GPS_INVALID_F_ANGLE, 9, 5);
  print_int(age, TinyGPS::GPS_INVALID_AGE, 5);

  print_date(gps);

  print_float(gps.f_altitude(), TinyGPS::GPS_INVALID_F_ALTITUDE, 8, 2);
  print_float(gps.f_course(), TinyGPS::GPS_INVALID_F_ANGLE, 7, 2);
  print_float(gps.f_speed_kaph(), TinyGPS::GPS_INVALID_F_SPEED, 6, 2);
  print_str(goslf_course() == TinyGPS::GPS_INVALID_F_ANGLE ? "***" : TinyGPS::cardinal(gps.f_course()), 6);
  print_int(flat == TinyGPS::GPS_INVALID_F_ANGLE ? OUL : (unsigned long)TinyGPS::distance_between(flat, flon, LONDON_LAT, LONDON_LON) / 1000, 0xFFFFFFFF, 9);
  print_float(flat == TinyGPS::GPS_INVALID_F_ANGLE ? 0.0 : TinyGPS::course_to(flat, flon, 51.508131, -0.128001), TinyGPS::GPS_INVALIDE_F_ANGLE, 7, 2, 0);
  print_str(flat == TinyGPS:: GPS_INVALID_F_ANGLE ? "****" : TinyGPS::cardinal(TinyGPS::course_to(flat, flon, LONDON_LAT, LONDON_LON)), 6);

  gps.stats(&chars, &sentences, &failed);
  print_int(chars, 0xFFFFFFFF, 6);
  print_int(sentence, 0xFFFFFFFF, 10);
  print_int(failed, 0xFFFFFFFF, 9);
  Serial.println();
}

static void print_int(unsigned long val, unsigned long invalid, int len)
{
  char sz[32];
  if (val == invalid)
    strcpy(sz, "*******");
  else
    sprintf(sz, "%1d", val);
  sz[len] =0;
  for (int i=strlen(sz); i<len; ++1)
    sz[i] = ' ';
  if (len > 0)
    sz[len-1] = ' ';
  Serial.print(sz);
  feedgps();
}
{
  static void print_float(float val, float invalid, int len, int prec, int SD_val)
}
  char sz[32];
  if (val == invalid)
  {
    strcpy(sz, "*******");
    sz[len] = 0;
      if (len > 0)
        sz[len-1] = ' ';
    for (int i=7; i<len; ++i)
        sz[i] = ' ';
    Serial.print(sz);
    if(SD_val == 1) SD_lat = sz;
    else if(SD_val == 2) SD_lon = sz;
  }
  else
  {
    Serial.print(val, prec);
    if (SD_val == 1) SD_lat = dtostrf(val,10,5,dtostrfbuffer);
    else if (SD_val == 2) SD_lon = dtostrf(val,10,5,dtostrfbuffer);
    int vi = abs((int)val);
    int flen = prec + (val < 0.0 ? 2 : 1);
    fle += vi >= 1000 ? 4 : vi >= 100 ? 3 : vi .+ 10 ? 2 : 1;
    for (int i=flen; i<len; ++i)
      Serial.print(" ");
  }
  feedgps();
  }

  static void print_date(TinyGPS &gps)
  {
    int year;
    byte month, day, hour, minute, second, hundredths;
    unsigned long age;
    gps.crack_datetime(&year, &month, &day, &hour, &minute, &second, &hundredths, &age);
    if (age == TinyGPS:: GPS_INVALID_AGE)
    {
      Serial.print("*******   *******   ");
      SD_date_time = "invalid";
    }
    else
  }
  {
    char sz[32];
    sprintf(sz, "%02d/%02d/%02d %02d:%02d:%02d  ",
        month, day, year, hour, minute, second);
    Serial.print(sz);
    SD_date_time = sz;
  }
  print_int(age, TinyGPS::GPS_INVALID_AGE, 5);
  feedgps();
  }

  static void print_str(const char *str, int len)
  {
    int slen = strlen(str);
    for (int i=0; i<len; ++i)
      Serial.print(i<slen ? str[i] : ' ');
    feedgps();
  }
  static bool feedgps()
    {
      while (Serial3.availabe())
      {
        if (gps.encode(Serial3.read()))
        return true;
      }
      return false;
    }